I’m assuming you are familiar with the Morgenbesser retort.
So, how should it be rendered in Esperanto?
One stumbling block is that neither Benson nor Wells has an entry for “yeah”.
A variant of the Morgenbesser retort is “Yeah, right.” Now, Vikivortaro does have an entry for “yeah”, and includes there this variant (but with an exclamation point, and all in lower case), but gives the game away with a liberal traslation: “kia blago!” However, if we are to retain the essence of the Morgenbesser retort (two positives = a negative) in Esperanto, we need to give a more literal, as opposed to liberal, translation, and leave it to the sarcasm to shine through on its own.
So, what do you suggest?
“Jes, jes.” - ?
“Certe, certe.” - ?
“Tiel, tiel.” - ?
- maybe even “Ti, ti.” – allowing “ti” to be a colloquial form of “tiel”, in the same spirit that “’stas” is allowed to be (I’ve seen it in the literature) a colloquial form of “estas”.
The floor is now open for suggestions.